It is known to epoxidze olefins such as propylene to form propylene oxide by reaction of propylene, hydrogen and oxygen using a catalyst comprised of palladium and platinum or titanium silicalite. See "Synthesis of Propylene Oxide from Propylene, Oxygen, and Hydrogen Catalyzed by Palladium-Platinum-Containing Titanium Silicalite" By: R. Meiers, U. Dingerdissen, and W. F. Holderich, Journal of Catalysis 176, 376-386 (1998). A feature of such prior procedures has been the reduction of the catalysts prior to use in the epoxidation reaction. The prior systems have been characterized by the undesirable formation of excessive amounts of propane which results from hydrogenation of the propylene reactant.